https://github.com/spring-projects/spring-framework: Spring Web MVC (Spring IO)
  • Juergen Hoeller 
/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.web.servlet.view;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;

import org.springframework.context.MessageSource;
import org.springframework.lang.Nullable;
import org.springframework.web.servlet.support.JstlUtils;
import org.springframework.web.servlet.support.RequestContext;


Specialization of InternalResourceView for JSTL pages, i.e. JSP pages that use the JSP Standard Tag Library. 
Exposes JSTL-specific request attributes specifying locale and resource bundle for JSTL's formatting and message tags, using Spring's locale and MessageSource. 
Typical usage with InternalResourceViewResolver would look as follows, from the perspective of the DispatcherServlet context definition: 
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
  <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
  <property name="prefix" value="/WEB-INF/jsp/"/>
  <property name="suffix" value=".jsp"/>
</bean>
<bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource">
  <property name="basename" value="messages"/>
</bean>

Every view name returned from a handler will be translated to a JSP
resource (for example: "myView" -> "/WEB-INF/jsp/myView.jsp"), using
this view class to enable explicit JSTL support.

The specified MessageSource loads messages from "messages.properties" etc
files in the class path. This will automatically be exposed to views as
JSTL localization context, which the JSTL fmt tags (message etc) will use.
Consider using Spring's ReloadableResourceBundleMessageSource instead of
the standard ResourceBundleMessageSource for more sophistication.
Of course, any other Spring components can share the same MessageSource.

This is a separate class mainly to avoid JSTL dependencies in InternalResourceView itself. JSTL has not been part of standard J2EE up until J2EE 1.4, so we can't assume the JSTL API jar to be available on the class path. 
Hint: Set the AbstractView.setExposeContextBeansAsAttributes flag to "true" in order to make all Spring beans in the application context accessible within JSTL expressions (e.g. in a c:out value expression). This will also make all such beans accessible in plain ${...} expressions in a JSP 2.0 page. 
Author:Juergen Hoeller
See Also:
Since:27.02.2003
/**
 * Specialization of {@link InternalResourceView} for JSTL pages,
 * i.e. JSP pages that use the JSP Standard Tag Library.
 *
 * <p>Exposes JSTL-specific request attributes specifying locale
 * and resource bundle for JSTL's formatting and message tags,
 * using Spring's locale and {@link org.springframework.context.MessageSource}.
 *
 * <p>Typical usage with {@link InternalResourceViewResolver} would look as follows,
 * from the perspective of the DispatcherServlet context definition:
 *
 * <pre class="code">
 * &lt;bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"&gt;
 *   &lt;property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/&gt;
 *   &lt;property name="prefix" value="/WEB-INF/jsp/"/&gt;
 *   &lt;property name="suffix" value=".jsp"/&gt;
 * &lt;/bean&gt;
 *
 * &lt;bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource"&gt;
 *   &lt;property name="basename" value="messages"/&gt;
 * &lt;/bean&gt;</pre>
 *
 * Every view name returned from a handler will be translated to a JSP
 * resource (for example: "myView" -> "/WEB-INF/jsp/myView.jsp"), using
 * this view class to enable explicit JSTL support.
 *
 * <p>The specified MessageSource loads messages from "messages.properties" etc
 * files in the class path. This will automatically be exposed to views as
 * JSTL localization context, which the JSTL fmt tags (message etc) will use.
 * Consider using Spring's ReloadableResourceBundleMessageSource instead of
 * the standard ResourceBundleMessageSource for more sophistication.
 * Of course, any other Spring components can share the same MessageSource.
 *
 * <p>This is a separate class mainly to avoid JSTL dependencies in
 * {@link InternalResourceView} itself. JSTL has not been part of standard
 * J2EE up until J2EE 1.4, so we can't assume the JSTL API jar to be
 * available on the class path.
 *
 * <p>Hint: Set the {@link #setExposeContextBeansAsAttributes} flag to "true"
 * in order to make all Spring beans in the application context accessible
 * within JSTL expressions (e.g. in a {@code c:out} value expression).
 * This will also make all such beans accessible in plain {@code ${...}}
 * expressions in a JSP 2.0 page.
 *
 * @author Juergen Hoeller
 * @since 27.02.2003
 * @see org.springframework.web.servlet.support.JstlUtils#exposeLocalizationContext
 * @see InternalResourceViewResolver
 * @see org.springframework.context.support.ResourceBundleMessageSource
 * @see org.springframework.context.support.ReloadableResourceBundleMessageSource
 */
public class JstlView extends InternalResourceView {

	@Nullable
	private MessageSource messageSource;


	
Constructor for use as a bean.

See Also:
  • setUrl
/**
	 * Constructor for use as a bean.
	 * @see #setUrl
	 */
	public JstlView() {
	}

	
Create a new JstlView with the given URL.

Params:
  • url – the URL to forward to
/**
	 * Create a new JstlView with the given URL.
	 * @param url the URL to forward to
	 */
	public JstlView(String url) {
		super(url);
	}

	
Create a new JstlView with the given URL.

Params:
  • url – the URL to forward to
  • messageSource – the MessageSource to expose to JSTL tags (will be wrapped with a JSTL-aware MessageSource that is aware of JSTL's javax.servlet.jsp.jstl.fmt.localizationContext context-param)
See Also:
  • JstlUtils.getJstlAwareMessageSource
/**
	 * Create a new JstlView with the given URL.
	 * @param url the URL to forward to
	 * @param messageSource the MessageSource to expose to JSTL tags
	 * (will be wrapped with a JSTL-aware MessageSource that is aware of JSTL's
	 * {@code javax.servlet.jsp.jstl.fmt.localizationContext} context-param)
	 * @see JstlUtils#getJstlAwareMessageSource
	 */
	public JstlView(String url, MessageSource messageSource) {
		this(url);
		this.messageSource = messageSource;
	}


	
Wraps the MessageSource with a JSTL-aware MessageSource that is aware of JSTL's javax.servlet.jsp.jstl.fmt.localizationContext context-param. 
See Also:
  • JstlUtils.getJstlAwareMessageSource
/**
	 * Wraps the MessageSource with a JSTL-aware MessageSource that is aware
	 * of JSTL's {@code javax.servlet.jsp.jstl.fmt.localizationContext}
	 * context-param.
	 * @see JstlUtils#getJstlAwareMessageSource
	 */
	@Override
	protected void initServletContext(ServletContext servletContext) {
		if (this.messageSource != null) {
			this.messageSource = JstlUtils.getJstlAwareMessageSource(servletContext, this.messageSource);
		}
		super.initServletContext(servletContext);
	}

	
Exposes a JSTL LocalizationContext for Spring's locale and MessageSource.

See Also:
  • exposeLocalizationContext.exposeLocalizationContext
/**
	 * Exposes a JSTL LocalizationContext for Spring's locale and MessageSource.
	 * @see JstlUtils#exposeLocalizationContext
	 */
	@Override
	protected void exposeHelpers(HttpServletRequest request) throws Exception {
		if (this.messageSource != null) {
			JstlUtils.exposeLocalizationContext(request, this.messageSource);
		}
		else {
			JstlUtils.exposeLocalizationContext(new RequestContext(request, getServletContext()));
		}
	}

}